Suspended animation is often referred to in the realms of space travel and science fiction, but a group of surgeons hope that similar techniques can be used to save lives.
This month, medical professionals at the UPMC Presbyterian Hospital in Pittsburgh, Pennsylvania will begin a suspended animation trial on 10 patients to try and buy surgeons time to save critical patients. Knife-wound and gunshot victims will be eligible for the trial, and they must have suffered a cardiac arrest and not respond to resuscitation.
"We are suspending life, but we don't like to call it suspended animation because it sounds like science fiction," says Samuel Tisherman, surgeon and leader of the trial. "So we call it emergency preservation and resuscitation."
Patient blood will be entirely replaced with a cold saline solution, cooling the body rapidly and stopping almost all cellular activity. At standard body temperature cells need a regular oxygen supply to produce energy and keep oxygen and blood flowing to the brain. At lower temperatures, cells need less oxygen because all chemical reactions slow down. If this hypothermic state is induced, surgeons should have more time to save a patient.
However, if someone is shot or stabbed, slowly cooling down a patient is not an option, as the heart has often already stopped due to rapid blood loss.
The new technique will pump saline through the heart and up to the brain. In roughly 15 minutes, the patient's temperature will have dropped to 10°C or 50°F, and all of their blood will have been replaced with saline. Clinically, they will be dead, with no metabolic reactions taking place in the body -- but this also forces cells to survive without oxygen, and instead through anaerobic glycolysis.
Anaerobic glycolysis is the breaking down of glucose without oxygen which sometimes takes place during vigorous physical activity. At low temperatures, cells can survive for hours using this technique. This gives surgeons extra time to fix the injury, before replacing the saline with blood, which will slowly reheat the body. If the heart does not restart, then the patient is resuscitated.
A final meeting between the surgical team will take place this week, and the 10 patients in the trial will be compared to another 10 who meet criteria but were not treated in the same way. The technique will then be refined on another 10 patients before the results are analyzed.
The trial is going ahead as the US Food and Drug Administration considers the situation exempt from informed consent, due to the fatal nature of such injuries. However, the trial has been advertized and people have the option to opt-out on the Acute Care Research website.
Read on: New Scientist
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